View Full Version : Solar Water Heating?
08-23-2011, 01:45 PM
I am the newest employee at Caleffi as their Southern Regional Sales Manager and am looking for solar water heating success stories.
08-23-2011, 10:32 PM
Most of my customers prefer to do laundry on cloudy/wet days, or in the evening. Most of the solar energy is available when I least need it. Unless I can somehow store a 24-hour supply of hot water, I don't expect to use solar water heating.
I would consider solar electric energy, however. In that case, I can generate power when the sun shines and "store" it by selling it to the utilities to offset when I'll use when the sun is not shining.
08-25-2011, 03:42 PM
Responses like this is why I joined this forum and thank you very much for your input. I am working on 'Rule of Thumb' storage calculations now because we have been involved in many projects where large storage tanks made the difference. Solar hot water can be harvested all day and stored for later use, exactly like you pointed out.
Would you be willing to provide a location size, washer count, hot water gpm use and other info for me as an example?
I currently store solar hot water in two large tanks at my house for home heating in the winter and domestic uses year-round. It works great!
08-25-2011, 10:56 PM
... Would you be willing to provide a location size, washer count, hot water gpm use and other info for me as an example? ...
I use about 15 gallons of water per dollar of washer revenue. My store fits in 1,800 sq ft, and contains 27 washers.
08-26-2011, 06:40 AM
I'm with Dave on this not being the best route to go. As he said the sun shines from about 9am till 4pm with any significant amount of thermal heat. Most of our customers come before 9am or after 5pm so the usage is almost exactly oposite the solar flux. Thus, the only way to make this work is with storage tanks and pumps. When you factor in the costs for the equipment the cost for the square footage to place these tanks I question the economics in most locations.
On the flip side solar electric makes a lot of sense, depending on what state you are in. If you are in CA or NJ solar electric wins hands down. In many other states it is great too, you have to check what incentives there are at the state level. I have had solar electric on my home for almost seven years and it has been a homerun as far as I am concerned. The system paid for itself in under 4 years and just keeps pouring out electricity at no cost to me. Since almost all states now have net metering you don't care when your usage is versus when your generation is as you just spin your meter backwards when you have a net excess of power.
08-26-2011, 01:56 PM
So you conserve energy by preheating the water but you waste energy by using electricity to run those water pumps for water circulation.
The other problem is how to repair or replace your roof with all those solar collector panels in the way.
08-31-2011, 02:46 PM
SolarDan, Looks like we're in the same field! Where in the SW are you located?
As has been mentioned before in this thread, consumption profile can certainly be an issue. I would note, however, that a well designed and insulated tank can act as a battery and hold much of the energy generated until the time of consumption. I currently have a project in SE Pennsylvania where we racked up 500 gallons of storage in the utility room, that sees almost no heat loss between generation and consumption (~95%).
As for the electric losses to run a pump, for a 'mat sized project you can afford to run a very small and efficient pump, probably 100W, running 8-12 hours a day - basically just another light bulb. Re-roofing is also an avoidable problem, at least the way we design systems panels are racked at least 18" (sloping up to 8 feet) above the roof, allowing roofers to work beneath them. We've had roofing work done around a number of our installations.
The main problem I see with solar thermal for laundromats is savings. Mat owners are well versed in the world of utilities and utility costs, you're not going to find someone unwittingly running electric boilers (which I've found elsewhere) and natural gas is dirt cheap here in the southwest. This can really throw off the savings, and return for the customer, for an outright purchase.
09-10-2011, 09:51 AM
I am in Texas and take care of the south east.
09-13-2011, 01:48 PM
I was very close to installing a system last year. That is, until the company found out who my utility company was. Evidently, they were too small to offer any sort of rebates. Only ~ 9000 customers on the grid. No rebate, no install.
09-13-2011, 05:37 PM
That's too bad, rebates can often make or break a project. Out of curiosity, what was the name of the company you were looking to work with?